[EKG] Misplaced Leads

1. LA-RA Reversal

• Lead I (造成RAD) & aVL completely inverted，
• aVR有可能是positive (因為 aVR和aVL互換)

2. LA-LL Reversal

• Lead III completely inverted
• Lead I的P-wave比 Lead II高 (因為 Lead I和II互換)
• aVF有可能是negative (因為 aVF和aVL互換)

3. RA-LL Reversal

• Lead I, II, III都是completely inverted
• aVR是positive

4. RA-RL Reversal

• Lead II 是flat-line
• Lead I & aVL變成Lead III的倒影

5. LA-RL Reversal

• Lead III 是flat-line

6. Arm-Leg Reversal

• Lead I 是flat-line

7. LL-RL Reversal

• No change

[EKG] Various Rate & Rhythm

[EKG] VT versus Abberancy

Favor VT:
1. Uniform QRS-polarity from V1~V6 統一QRS的axis是Positive或Negative 

2. Capture beat 一堆wide QRS中有narrow QRS

3. Fusion beat   一堆wide QRS中有"中等寬度" QRS

4. AV-dissociation   一堆wide QRS中有occasional P wave

[EKG] Ischemia? Infarction?

1. RV-infarction likely:
(a) STE in lead III > II
(b) STE in lead V1 > V2
(c) STD in lead V2 +STE or isoelectric in lead V1

2. WPW mimicking as AMI
(a) INFERIOR leads有large Q-wave   ==> IMI
(b) V1有large R-wave                         ==> PMI

3. STE in aVR: 
(a) + aVL: Left-Main
(b) + V1: Left-Main or proximal-LAD, 但若aVR > V1: Left-Main

4. Reciprocal changes (STD + TWI) in aVL:
(a) Inf. MI
(b) Ant. MI
(c) LVH
(d) LBBB
(e) Digitalis use

5. New Tall T-wave in V1: NEW-UPright T-wave in V1 + T-wave:V1>V6
(a) Ischemia (LCx or RCA)
(b) LVH
(c) LBBB
(d) High left ventricular voltage (Young athlete)
(e) Normal variant

6. Posterior-MI: 看lead V1~V3有無 (STD + UPright-T + Tall R-wave)

[EKG] Arrhythmogenic D/Dx for Syncope

1. Dysrhythmia

2. Ischemia

3. WPW

4. Long-QT

5. Brugada

6. HoCM

7. (Arrhythmic right ventricular displacement)

[EKG] Electrolytes

Hypokalemia

Prolonged QT (Due to U waves)

ST-segment Depression 

Biphasic T-waves (Down then up, unike Wellen’s waves)

PVC’s, ventricular arrhythmias


Hyperkalemia
Tall T-wave
Prolonged PR
P-wave flattening
QRS widening
Sine wave
VF

Hypercalcemia

Short QT

ST-Elevation

[EKG] 整理自 ECGs for the Emergency Physicians Part 1

1. LVH strain pattern:
(a) Lateral leads: STD & Asymmetric TWI
(b) Right precordial leads: STE

2. Prominent R wave in lead V1 (R/S-ratio > 1), D/dx:
(a) RVH
(b) RV-strain/dilatation
(c) HOCM
(d) Dextrocardia
(e) Ventricular ectopy
(f) WPW
(g) Misplaced precordial leads
(口訣: WORD)
W: WPW, O: HOCM, R: RVH/RV-strain/RBBB, D: Dextrocardia

3. Acute massive pulmonary embolism likely:
(a) Tachycardia
(b) RAD
(c) incomplete RBBB
(d) S1Q3T3
(e) TWI in inferior and anteroseptal leads

4. Cyclic antidepressant overdose likely:
(a) Tachycardia
(b) RAD
(c) R-wave in lead aVR > 3mm
(d) QRS-prolonged

5. HOCM likely: (以下findings都是ventricular septum hypertrophy所致)
(a) large QRS in ALL leads
(b) tall R-wave in lead V1 & V2
(c) deep Q-wave in INFERO-LATERAL leads

6. Digoxin toxicity likely:
(a) Occasional VPCs
(b) "Hockey-stick" like appearance of terminal portion of R-wave
(c) Complete heart block with regular junctional or ventricular escape
(d) Atrial tachycardia with variable AV-block

7. WPW mimicking as AMI
(a) INFERIOR leads有large Q-wave   ==> IMI
(b) V1有large R-wave                        ==> PMI

[EKG] 區分pericarditis VS STEMI

看到STE要如何區別AMI及Pericarditis:

1. (有以下5點任1點就rule in AMI)

(a) ST-Depression (不看V1 & aVR)

(b) STE 是convex-upwards or horizontal

(c) STE in lead III > II
(d) R-T sign or "check mark sign" (R之後沒有明顯的ST就接到T-wave)
(e) new Q-waves

2. (有以下2點任1點就rule in pericarditis)
(a) PR-Depression in multiple leads 
(b) T-P segment depression or "Spodick's sign"

[EKG] Sgarbossa Criteria (含modified)

(EKG of normal LBBB)


Sgarbossa Criteria (> 3 points才像STEMI)
[5-points] > 1 mm STE Concordance (any leads除了V1~3)
[3-points] > 1 mm STD Concordance (V1~3) (因為正常的LBBB其V1~3是STE)
[2-points] > 5 mm STE DISCONCORDANCE

Modified Sgarbossa Criteria (Sen. 59 --> 85%, Spec. 99 --> 96%)
把2-point的criteria改成: STE DISCONCORDANCE in lead V1~4且同時符合以下criteria:
(a) ST / S ratio > 0.2
(b) > 2 mm STE

[EKG] Amal Mattu's Weekly 整理

1. 看到 Irregular rhythm (在下A.fib這個診斷之前)，一定要先看是否有 "clumps" (Regularly-irregular); D/dx:

(a) Premature beats (通常會在clumps之後造成pauses)

(b) Mobitz (2nd degree AV block)

2. PR-interval是區分AV-block的主角 (看lead V1)

(a) Fixed: 1st degree AV block, 2-2 AV block

(b) Prolonging: 2-1 AV block

(c) Variating: 3 AV block

3. 若對區分2-1及2-2 AV block有疑慮，就看"沒有傳下去的P"的"前一個"及"下一個"PR-interval長度: (相等: 2-2, (b) 下一個比前一個長: 2-1)

4. 生平第一次發生"seizure"要作EKG來rule-out dysrhythmia

5. AV-dissociation (atrial rhythm & ventricular rhythm各跳各的) 不一定是complete heart block；若atrial rhythm傳的下去就是AV-dissociation without complete heart block (會看到QRS的morphology改變)

6. RBBB有看到STE或V1~3以外的lead有STD皆異常 (正常在V1~3是會有STD及TWI)

7. 在infero-antero-lateral lead (II,III,aVF,V3~6)有看到isolated TWI表示有pulmonary hypertension; 若看到new TWI則要想到pulmonary embolism

8. 看到 (low voltage + tachycardia) 要先rule-out pericardial effusion

[EKG] Pediatric EKG

1. Large R wave in V1~2, Small S wave in V5~6

2. TWI at V1~3, through age 8

3. 若是在V1有看到upright T, 則是RVH

[EKG] Differential Diagnosis

Leftward Axis Deviation
1. Pacemaker
2. WPW
3. Inferior MI
4. LVH
5. LBBB
6. LAFB
7. Hyperkalemia
8. (Normal variant)

Rightward Axis Deviation
1. Lateral MI
2. WPW
3. RVH
4. LPFB
5. Pulmonary embolism
6. COPD
7. Na-channel blocker
8. Septal defect
9. Hyperkalemia

Wide QRS
1. BBB
2. WPW
3. Pacemaker rhythm
4. Na-channel blocker
5. LVH
6. Ventricular ectopic
7. Hyperkalemia or Acidosis

Short QT
1. Hypercalcemia
2. Digoxin Toxicity
3. (Congenital)

QTc-Prolongation
1. Electrolyte imbalance: HYPO-(K, Ca, Mg)
2. IICP
3. Medication: type Ia (quinidine, procainamide), type III (amiodaraone)
4. Hypothermia
5. (Congenital)

T-wave Inversion
1. WPW
2. Hypokalemia
3. CAD
4. Abnormal repolarization: BBB, pacemaker, ventricular hyperthrophy
5. ICH
6. Pulmonary disease: Pul. HTN, Hyperventilation, Pneumonia, Pul. embolism

ST-Elevation
1. STEMI
2. Peri-/myocarditis
3. LVH
4. LBBB
5. Ventricular aneurysm
6. Brugada
7. Hyperkalemia
8. CNS-effect (SAH)
9. Benign early repolarization
(口訣: LAP BAND)
LVH,LBBB / AMI / Pericarditis / Brugada,BER /Aneurysm(LV) / Neurological (SAH) / Drugs(cocaine)

ST-Depression
1. NSTEMI
2. Strain (due to ventricular hypertrophy)
3. Digitalis effect
4. Ischemia
5. Hypokalemia

Low-voltage 

definition:(QRS的amplitude): (a) lead (I + II + III) < 15 mm, or  (b) lead (V1 + V2 + V3) < 30 mm

1. "low power"
(a) Myxedema
(b) Cardiomyopathy
(c) Infiltrative disease (Sarcoidosis)
2. "blocked conduction"
(a) (air) COPD
(b) (fluid) pericardial/ pleural effusion
(c) (fat) obesity

[EKG] Brugada Syndrome

Brugada syndrome has 3 different ECG patterns:

• Type 1 has a coved type ST elevation with at least 2 mm (0.2 mV) J-point elevation a gradually descending ST segment followed by a negative T-wave.
• Type 2 has a saddle back pattern with a least 2 mm J-point elevation and at least 1 mm ST elevation with a positive or biphasic T-wave. Type 2 pattern can occasionally be seen in healthy subjects.
• Type 3 has either a coved (type 1 like) or a saddle back (type 2 like) pattern with less than 2 mm J-point elevation and less than 1 mm ST elevation. Type 3 pattern is not uncommon in healthy subjects.
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